Analysis Of Key Process In Construction Of Large-scale LNG Tank

In recent years, the natural gas in the energy market shows a strong momentum,bringing huge benefits to natural industry chain. However, LNG storage tank becomesthe limiting factor in the development of gas industry chain as the receiving terminal.It possesses the characters that large site, high construction costs, long design cycle,complex building and high technical requirements. Therefore, it is significant tostrengthen the research of LNG storage tanks to promote the development of LNGindustry in China.The height of LNG tank can reach to50m, and the diameter can reach to82m.LNG tank is consisted of pile cap, primary containment, secondary containment androof.etc. Pouring of concrete about secondary containment and pile cap is referred tomass concrete grouting. Inchoate cracks have an iMPact on the durability of LNGtank which was resulted by the cement hydration in the process of construction,causing the through cracks of slab and wall. Inchoate cracks affect the later useseriously. Beyond that, applying pressure also leads the concrete to crack in theprocess of concrete pouring of roof. Thus, it is necessary to simulate temperaturedistribution, and stress in the hydration process of slab and wall. Moreovermechanical analysis in the process of concrete pouring of roof is important.In this paper, the hydration heat of different parts was analyzed by using generalfinite element software ANSYS toward LNG tank. The main work is listed as follows:1. Do collection of literature about concrete hydration heat and LNG storage tankconstruction at home and abroad, understanding the development and construction ofthe new technology;2. Three-dimensional model was established for slab construction andtwo-dimensional axisymmetric model was established for wall to simulate thehot-structure coupling. One-four model was established for roof construction.Conclusion reached as following:1. There are two programs to pouring concrete for slab: pouring inside-out andout-inside. But both the cracking index of the two programs are lesseer than1, somore steel would be added to prevent cracking. Conclusion shows that smallertemperature stress happened to the out-inside program which can shorten theconstruction schedule, and reduce construction cost. 2. The cracking index of1ststage to9thstage in the wall is smaller than1.Temperature drop is smaller than25℃in the beam. Experienced ratio ofreinforcement is larger than that needed to control cracking, so no more steel wouldbe needed.3. Stable pressure applied to the roof during the construction of roof pouring canmake the cracking index smaller than1at the early stage of construction. So differentpressure would be needed in different construction stage.